Pressure cooker quick release vs. "cold water" pressure release

"Cold Water Release Method: for certain delicate foods and veggies, you will want to release the pressure as quickly as possible in order to stop the cooking process. The quickest way to do this is to take the pressure cooker from the stove to the sink and run cold water over the lid"

QUESTION:

How the heck is that faster than just turning the dial to the 'release steam' position? The pressure is evacuated in about 30 seconds.